Protein network analysis and engineering decarboxylases for cadaverine and putrescine production

【Author】

Byung-Gee Kim;Eun Young Hong;Roopali Upadhyay;Jin Young Kim;

【Abstract】

Lysine/Ornithine decarboxylases(Ldc/Odc)are very useful enzymes for synthesizing cadaverine and putrescine,which are C5 and C4 diamines,respectively.To maximize cadaverine production from lysine,improving enzyme activity and stability is necessary in alkaline pH.To obtain a higher enzyme activity,we examined the mechanisms that regulate the activity of Ldc.Compared to the high specific activity at low pH(pH 5.8),the enzyme activity sharply decreased as the pH increased.Since the Ldc enzyme reaction tends to make the reaction solution basic,increasing the activity of Ldc at high pH is required for an optimal production.A rational enzyme engineering approach was undertaken to improve both activity and stability activity of Escherichia coli Ldc towards its physiological substrate at pH values above 6.The site specific mutation sites were guided by mechanistic insights and the knowledge of the enzyme structure obtained from previously reported X-ray crystallographic experiment(PDB 3n75).In addition,protein network analysis was integrated to narrow down possible mutation sites for improving the stability of the Ldc.The results showed that insertion of disulfide bonds in the N-terminal loop region greatly improved its stability To maximize putrescine production from ornithine using Ode,improving enzyme activity and substrate(omithinw/lysine)selectivity is necessary in alkaline pH to reduce the impurity content of cadaverine during the distillation of putrescine.In order to improve the substrate selectivity for ornithine over lysine,various different approaches such as factorB and Caver were used and their results were presented.

【Keywords】

cadaverine;;lysine decarboxylase;;putrescine;;ornithine decarboxylase(ODC);;molecular evolution;;protein network analysis

References

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Total: 5 articles

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  • [4] Kanjee Usheer;;Gutsche Irina;;Alexopoulos Eftichia;;Zhao Boyu;;El Bakkouri Majida;;Thibault Guillaume;;Liu Kaiyin;;Ramachandran Shaliny;;Snider Jamie;;Pai Emil F;;Houry Walid A, Linkage between the bacterial acid stress and stringent responses: the structure of the inducible lysine decarboxylase, The EMBO journal, EMBO Journal (EMBO Journal)

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